The present invention relates to a sheet cutting device that cut several sheets of paper, to a sheet finisher equipped with the sheet cutting device, and to an image forming system provided with the sheet cutting device.
A sheet finisher carrying out various types of post-processing (finishing) is connected to a high speed image forming apparatus such as an image forming apparatus employing the electro-photography method, and a multiple-function image forming system has come into wide use that make it possible to carry out within a single apparatus various types of finishing operations such as punching, stapling, and folding of paper sheets on which images have been formed.
A sheet finisher is available that include a sheet cutting device for aligning and cutting the edges of stacks of sheets having a plurality of sheets after carrying out various types of finishing operations such as hole punching, stapling, folding, etc., and the following types of devices are known as sheet cutting devices.
In other words, a cutting device for cutting a plurality of sheets of paper stacked one on top of the other on a table, in which the stack of paper sheets is cut by a cutter that rises from below in a diagonally upward direction while the stack of sheets is being kept pressed by a sheet pressing member that comes down from above the sheets while being guided by vertical guides, and the sheet pressing member and the cutter are each provided with a separate motor whose rotation is transmitted to a screw, the nut engaging with that screw is coupled by a link to the sheet pressing member or the cutter, thereby making it possible to drive them using even a small motor. (See, for example, Patent Document 1.)
Patent Document 1: Japanese Non-Examined Patent Publication No. 2003-136471.
In the configuration disclosed in Patent Document 1, size reduction of the apparatus is being aimed at because the drive can be realized using small motors and the apparatus can be used as a peripheral device of office equipment used in offices with limited installation space. However, the paper shreds generated at the time of cutting may not drop down but may get adhered to the table or to the paper pressing member. Because, the static electricity generate while carrying out the different processes of punching, stapling, folding, etc., or the static electricity generate due to the friction between the table and the sheet pressing member at the time of insertion into the cutting section, or the static electricity generate at the time of cutting.
If the cutting operation is carried out with the paper shreds adhering to the table or to the paper pressing member, the paper shreds leave their marks on the stack of sheets because the force of pressing the stack of sheets is large, and hence the finishing quality will be lost. Further, because of the adhered paper shreds, when a new stack of sheets is inserted into the cutting section, the outer sheets in a stack of sheets may get slightly shifted or may get folded.